A disc filter element of this general kind is known from GB-A-894 318. The openings provided in the filter element body thereof are arranged to provide optimum distribution of suction during filtering and of compressed air for removing the filter cake.
Different fiber types provide most different flows through the filter. Thus, e.g. pure cellulose (long fibers) passes through typically 400 l/m.sup.2 min, whereas mechanical pulp typically passes through only 40 l/m.sup.2 min.
To adapt a filter of the known kind to different filtering tasks (fiber or suspension types) is expensive as well as technically complicated.